A conventional deck lid or hood of a vehicle is generally quite heavy. Accordingly, they are pivotally attached to a vehicle body using hinge strap assemblies and are typically spring biased toward an open position. This biasing eases the burden on a vehicle operator in opening a deck lid or hood.
A first or proximate end of a hinge strap is pivotally attached relative to the vehicle body. A second or distal end is affixed to the deck lid or hood. With respect to hinge strap assemblies for deck lids, hinge boxes generally bolt beneath the back shelf and rear window of a vehicle. A pair of spaced apart ears on each hinge box supports a pivot pin which extends through the proximate end of a respective hinge strap. These hinge boxes are relatively complex in configuration and rather expensive to manufacture.
A common method of biasing the hinge straps open is to provide a pair of cooperating torque rods. One end of each torque rod is anchored to the vehicle or a hinge box adjacent a respective hinge strap. The other end of each torque rod is attached to the respective hinge strap on the opposite side of the vehicle. Consequently, each torque rod extends across the width of the vehicle criss-crossing with the other torque rod.
When the deck lid or hood is closed, one end of each torque rod is moved through an arcing or curvilinear translational motion causing another portion of the torque rod to twist in torsion thereby storing energy. When the deck lid or hood is opened, the torque rods are unwound releasing energy and assisting in biasing the deck lid or hood to an open position.
Several drawbacks exist with the above described hinge strap as assemblies and their torque rods or springs. First, torque rods which span transversely across the width of a vehicle from hinge strap to hinge strap occupy a significant amount of space in a vehicle trunk or engine compartment. Thus, these torque rods can cause interference in the centerline of a vehicle containing these criss-crossing torque rods. Second, these torque rods are generally designed to have a fixed spring rate and are not readily variable in stiffness and energy storage capacity. Finally, using hinge boxes adds significantly to the expense and complexity of hinge strap assemblies.
The present invention is intended to overcome these shortcomings.